Liquid



Patented Nov. 18, 1952 UNITED STATES PATENT F FICE'T.

LIQUID-DETERGENT COMPOSITION.

Herbert-L. Sanders; Phillipsburg -Nrl, assignor to-GeneralAniline & FilmCorporation, New York,..N: Y2, a corporation. of. Delaware No Drawing.Application. July 7,1949, Serial No. 103,531

'7" Claims. 1 i

This invention relates to detergents and more particularly to liquiddetergents for --use in the mechanical washing and the like.

In mechanical washing machines. such as dishwashing machines, it hasbeen customary to use mixtures of inorganic saltssuch as sodiummetasilicate, trisodium-phosphate, sodium carbonate and sodiumpolyphosphates. compositions the alkaline 1 components areresponsible-for the larger part of thecleaning operation andfunction'by-virtue of their power-t0 saponify fats, dissolveproteinsy'eto. These a1- kalies, however, form precipitates byinteraction with the calcium and magnesium-salts presentin most-naturalwaters. Furthermore, thehi-gh alkalinityforms soaps by saponification ofthe fatty oils present and these soaps in-turn react with the otherhardness to form sticky soap curds.

Inorder'toavoid all this" it has become customary to acid sodiumpolyphosph-atcs to -thealkaline salts. The relatively neutralpolyphosphates (sodium hexametaphosphate, sodium tripolyphosphate,sodium tetraphosphate, etc.) sequester the water hardness by formingcomplexes with the calcium and magnesium ions which effectivelyremove-them from the sphere of action. While thisis definitely animprovement. over simple alkalies. nevertheless thev resultantproductsstill-leave much to be desired. Having littleor no wetting powerthe filmof solution left after washing tends to breakup into droplets; due tothe high salt content, these drops leave residual salts or so-calledwaterspots on drying. The large salt crystals normally present in theseproducts tend to dissolve rather slowly, and if an undissolved crystalcomes into contact with aluminumwaraor sometimes.

silverware,.pitting is likely to occur. The high alkalinity also tendsto slowly remove glass from fine china and will sometimes etch soft glssware over long periods.

It has been proposed in the past to use organic detergents in additionto the alkalies, but organic detergents generally give far too much foamto be practical. Furthermore, it is desirable to provide a liquiddetergent composition because of the ease of dissolving detergents inthe machine but many organic detergents gel in concentrated solutions.

It is an object of the present invention to provide an improved liquiddetergent composition.

It is a further object of the present invention to provide an improvedliquid detergent composition containing an organic detergent.

It is a further object of the present invention to provide an improvedliquid detergent composi- In these in range from 2 to 10 parts. Theamount of Waterin the composition may vary in range from to 88 parts. Itwill be understood, however, that the water content of the compositionstated is the minimum amount adaptedto givea concentrated solution, butany amount ofwater may be added since the solution is water-soluble. Inactual practice the minimum amount of water is used in the compositionsold commercially,.but the addition of larger amounts of water is withinthe scope of the invention.

The following examples are illustrative of .the inventionbutit will beunderstood that substitutionsand variations may be made within the,

scope of the claims.

Example 1 10% N-palmitoyl-N-cyclohexyl taurate 4 10% Tetrapotassiumpyrophosphate 2% Sodium metasilicate 78% Water This formed a.clear,moderately. viscous solutron stable on storage. forseveral months. When1 oz..of such a solution was used as the detergent in a GeneralElectricor Hotpoint household.dish-,

washin machine, it was. found thatlittle or no foam resulted,.fat and.protein soils werecom-r pletely removed, and the dishes and glassware:drained evenly after washing and rinsing to give bright, spot-freesurfaces on drying.

Example 2 5% N-palmitoyl-N-cyclohexyl taurate 15% Tetrapotassiumpyrophosphate 80% Water This composition was also clear and stable. When1 oz. of such a solution was used in a General Electric or Hotpointhousehold dishwashing machine, it was found little or no foam resulted.Fat and protein soils were completely removed and the dishes andglassware were bright and spot-free on drying.

The advantages of organic detergents in dishwashing are twofold: In thefirst place, the synthetic organic detergents do not react with waterhardness to give film-forming precipitates, and some of them may in factdisperse and wash away such precipitates as may be formed by othermaterials present. In the second place, a trace of these detergents willusually be left after washing and rinsing and, by their wetting power,will cause the water film to spread or "drain uniformly instead ofbreaking into droplets, thus ensuring rapid drying and absence of waterspotting. The excessive foaming of previously available syntheticdetergents and wetting agents has, however, interfered with efficientperformance of the machines and caused unsightly bubbling throughhinges, etc. besides making rinsing difficult. I have now discoveredthat a new synthetic detergent, viz. N-palm'itoyl-N-cyclohexyl taurateis admirably suited for this application due to its combination of goodwetting and detergent properties with exceptionally low foaming power.

In order to combine this material with mild alkalies and at the sametime eliminate the presenceof difiicultly soluble crystals it was foundpreferable to prepare the new composition in liquid form. In certaintypes of household machines only a liquid detergent is in fact capableof acting, due to inadequate agitation of the wash water. It was soonfound, however, that suitable solutions could not readily be made. Inthe first place, the new organic detergent was not easily dissolved inwater: solutions containing about ten percent of this compound variedfrom thick gels to white pastes, depending on the purity of the plantbatches. In many cases even five percent solutions were turbid andgelatinous, and tended to separate out on standing. On adding alkaliesto such systems the condition became even worse. Thus the addition of5-10% potassium carbonate to a gel of the detergent caused separation ofan oily phase; addition of sodium tripolyphosphate caused a stiffeningor livering to occur; tetrasodium pyrophosphate ave only a white paste.The following compounds were thus found to be incompatible with the 10%N-palmitoyl-N-cyolohexyl taurate solutions: sodium carbonate, potassiumcarbonate, dipotassium hydrogen phosphate, sodium silicate, potassiumsilicate, sodium hydroxide, potassium hydroxide, tetrasodiumpyrophosphate, sodium tetraphosphate, trisodium phosphate, sodiumsesquicarbonate, sodium hexametaphosphate, sodium bicarbonate and sodiumtripolyphosphate.

Although 5% solutions of the organic detergent appeared to be morecompatible with some of these, such as trisodium phosphate, thecombinations were cloudy, and gelling began to set in after several daysstorage. Potassium tetraborate showed some compatibility but gelledeventually.

It was surprising that only one alkali possesses the desirable propertyof thinning out and clarifying the gelatinous solution of the organicdetergent and remaining indefinitely compatible with it on storage. Thisalkali is tetrapotassium pyrophosphate. The preferred dishwashingcompositions of this invention are therefore aqueous solutions ofN-palmitoyl-N-cyclohexyl taurate and tetrapotassium pyrophosphate. Insome cases a small amount of sodium metasilicate may also be added toprevent tarnishing of aluminum, the potassium pyrophosphate permittingthe addition of this normally incompatible alkali.

What I claim is:

1. A liquid detergent composition adapted for use in mechanicaldishwashing operations comprising from 5 to 20 parts ofN-palmitoyl-N-cyclohexyl taurate, from 5 to 20 parts tetrapotassiumpyrophosphate and water.

2. A liquid detergent composition adapted for use in mechanicaldishwashing operations comprising from 5 to 20 parts ofN-palmitoyl-N-cyclohexyl taurate, from 5 to 20 parts tetrapotassiumpyrophosphate, from 2 to 10 parts sodium metasilicate, and water.

3. A liquid detergent composition adapted for use in mechanicaldishwashing operations comprising from 5 to 20 parts ofN-palmitoyl-N-cyclohexyl taurate, from 5 to 20 parts tetrapotassiumpyrophosphate, and at least 50 parts water.

4. A liquid detergent composition adapted for use in mechanicaldishwashing operations comprising from 5 to 20 parts of N-palmitoyl-N-cyclohexyl taurate, from 5 to 20 parts tetrapotassium pyrophosphate,from 2 to 10 parts sodium metasilicate, and at least 50 parts water.

5. A liquid detergent composition adapted for use in mechanicaldishwashing operations comprising from 5 to 20 parts of N-palmitoyl-N-cyclohexyl taurate, from 5 to 20 parts tetrapotassium pyrophosphate,from 2 to 10 parts sodium metasilicate, and from 50 to 88% water.

6. A liquid detergent composition adapted for use in mechanicaldishwashing operations consisting essentially of 10%N-palmitoyl-N-cyclohexyl taurate, 10% tetrapotassium pyrophosphate, 2%sodium metasilicate, and 78% water.

7. A liquid detergent composition adapted for useun mechanicaldishwashin operations consisting essentially of 5%N-palmitoyl-N-cyclohexyl taurate, 15% tetrapotassium pyrophosphate and80% water.

HERBERT L. SANDERS.

REFERENCES CITED The following references are of record in file of thispatent: the

UNITED STATES PATENTS Number

1. A LIQUID DETERGENT COMPOSITION ADAPTED FOR USE IN MECHANICALDISHWASHING OPERATIONS COMPRISING FROM 5 TO 20 PARTS OFN-PALMITOYL-N-CYCLOHEXYL TAURATE, FROM 5 TO 20 PARTS TETRAPOTASSIUMPYROPHOSPHATE AND WATER.